I. Field of the Invention
The present invention relates generally to truss assemblies and, more particularly, to a truss assembly for the drive axle of an automotive vehicle.
II. Description of the Prior Art
Many types of recreational vehicles, such as jeeps and similar vehicles, employ a four wheel drive system. Consequently, the front axle assembly for such vehicles includes a differential assembly having a pair of elongated axle housings which extend laterally out from opposite sides of the differential. A drive axle, of course, is carried in each axle housing and a wheel is drivingly connected to the free end of each axle.
The axle housings are typically tubular and cylindrical in cross-sectional shape and are secured to the differential housing by welding. The welded connection between the axle housings and the differential forms a relatively weak spot in the construction of the front wheel drive for the vehicle.
Recreational vehicles, by their very nature, are often driven in off road conditions where the terrain is extremely uneven. In many cases, such vehicles are driven over small hills so that the entire vehicle becomes airborne before it again contacts the ground.
Such driving conditions, however, can be particularly damaging to the front wheel drive assembly for the vehicle. In particular, when the vehicle's front wheels become airborne and again contact the ground, the downward force of the vehicle tends to bend and flex the axle housings upwardly with respect to the differential and such flexing can break the welded connection between the axle housing and the differential. Although similar stresses are also imposed upon the rear axle drive assembly, the problem of breakage of the axle housing is particularly acute for the front axle assembly since the weight of the vehicle engine is positioned directly above the front axle.
In order to reduce the occurrence of axle breakage, there have been a number of previously known truss assemblies which attach to both the front and rear drive axles for such vehicles and which are designed to minimize the flexing of the axle housings with respect to the differential. These previously known truss assemblies, however, have not proven entirely satisfactory in operation.
One type of previously known axle truss assembly comprises a pair of clamps and each clamp is secured to the axle housing adjacent one of the wheels. Thereafter, an elongated rod is secured at one end to one clamp and, at its other end, to the other clamp and so that a mid portion of the rod contacts the problem of the differential housing. In operation, the additional strength of the rod secured across the axle assembly is intended to add rigidity to the axle assembly and minimize upward bending of the axle housings with respect to the differential.
This previously known type of axle truss assembly, however, is not proven entirely satisfactory in operation. One disadvantage of this previously known truss assembly is that the clamp provides only a single point connection between the rod and each axle housing thus only marginally reduces the stresses imposed upon the axle housing during off road operation of the vehicle. Moreover, these previously known truss assemblies have employed relatively small diameter rods, for example, a one-half inch diameter rod, and since the rod extends substantially entirely across the axle assembly, such rods only minimumly add to the overall strength of the axle assembly. For this reason, the breakage of the drive axle assembly particularly between the axle housing and the differential housing is a common event even when these previously known truss assemblies are employed.
These previously known truss assemblies are further disadvantageous in that the bar stretches after the prolonged use thus reducing the axle support provided by the truss assembly.